Danish computer-oriented astronomer who became a full-time computer scientist in the late 1950s. One of the developers of AlgolSixty and of the BackusNaurForm. Author of the paper "ProgrammingAsTheoryBuilding" (1985). Many of his computer-related papers are collected in the book "Computing: A Human Activity - Selected Writings From 1951 To 1990" ISBN 0-201-58069-1 (see http://www.naur.com/comp/default.html for a table of contents).